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Inside Macintosh: Devices /

Chapter 4 - SCSI Manager 4.3 / SCSI Manager 4.3 Reference

SCSI Manager 4.3 Functions / Client Functions

SCSIResetDevice

You use the SCSIResetDevice function to reset a SCSI device.

OSErr SCSIAction(SCSI_PB *scsiPB);

scsiPB

A pointer to a SCSI Manager parameter block.

-->	scsiPBLength	UInt16	The size of the parameter block.
-->	scsiFunctionCode	UInt8	The SCSIResetDevice function selector code (0x12).
<--	scsiResult	OSErr	The returned result code.
-->	scsiDevice	DeviceIdent	The device identification record.
-->	scsiCompletion	CallbackProc	A pointer to a completion routine. If set to nil, the function is executed synchronously.
-->	scsiDriverStorage	UInt8 *	Optional pointer to the device driver's private storage.

DESCRIPTION

The SCSIResetDevice function attempts to send a BUS DEVICE RESET message to the target. If the device is currently on the bus, the SIM asserts the /ATN signal and sends the message at the next message-out phase. If the target is not on the bus, the SIM selects it and sends an IDENTIFY message followed by a BUS DEVICE RESET message.

SPECIAL CONSIDERATIONS

The BUS DEVICE RESET message clears all I/O transactions for all logical units of the target device. This function may result in data loss and should be used only to restore operation in the event that a device fails to respond to other messages.

RESULT CODES

noErr	0	No error
scsiBusInvalid	-7869	The bus ID is invalid
scsiRequestInvalid	-7870	The parameter block request is invalid
scsiPBLengthError	-7872	The parameter block is too small for this SIM
scsiQLinkInvalid	-7881	The qLink field was not 0
scsiMessageRejectReceived	-7923	REJECT message received